A hybrid-electric vehicle includes a traction battery for supplying power for propulsion. To maximize battery life, the traction battery may be operated within a limited state of charge (SOC) range. As the battery ages, the power capability of the battery may be reduced. An SOC range selected at the beginning of battery life may not be adequate as the battery ages. A battery controller may attempt to compensate for battery aging by modifying the SOC range that is allowed. Battery controllers may adjust the operational SOC window to ensure that a maximum amount of power is available within the SOC window. This maximum amount of power may decrease as the battery ages, but the controller may attempt to select an SOC range in which the battery may provide power for propulsion. The focus of certain prior control schemes is to select the SOC range in which the traction battery may supply power for propulsion.